Decades after Stephen Hawking predicted that black holes should slowly leak radiation, researchers recreated a black hole inside a strand of optical fibre — and watched it push back.
Hawking radiation is the theoretical glow that black holes should emit as they slowly lose mass and eventually evaporate. The trouble is that for any black hole in the real sky, the signal is vanishingly faint — drowned out by the rest of the universe. Detecting it directly may be impossible for the foreseeable future.
So physicists built stand-ins.
In 2026, a team including researchers at Paderborn University, led by Lorenzo M. Procopio, used a length of optical fibre as a model of a black hole. Inside the fibre, a specially shaped light pulse creates conditions that mimic an event horizon — the point of no return. Particles riding on that light behave, mathematically, like the particles around a real black hole.
The result, published in Nature, went further than previous analogue experiments. The team observed not just the Hawking-like radiation, but also its backreaction: a tiny recoil of the source once the radiation is emitted. That recoil is the very mechanism that drives a real black hole to shrink and evaporate.
The backreaction is the missing step. Hawking’s original calculation showed that radiation exists, but it did not fully describe how the radiation drains energy from the black hole itself. Seeing the effect in the lab confirms the mechanism and reveals that the coupling between the radiation and its “gravity” is surprisingly direct — physicists call it a biquadratic relationship.
It is important to keep the limits clear. The fibre experiment is an analogue black hole: it reproduces the relevant physics, but it is not a gravitational object. It cannot replace observation of an actual black hole, but it gives scientists a controlled setting to test ideas that are otherwise pure theory.
In effect, the experiment lets us rehearse the physics of black-hole death on a desk — a rare chance to watch one of nature’s most dramatic processes play out, in miniature, in a laboratory.